Solutions 20: Modeling Using Variation

Solutions to Try Its

1. [latex]\frac{128}{3}[/latex]

2. [latex]\frac{9}{2}[/latex]

3. x = 20

Solutions to Odd-Numbered Exercises

1. The graph will have the appearance of a power function.

3. No. Multiple variables may jointly vary.

5. [latex]y=5{x}^{2}[/latex]

7. [latex]y=10{x}^{3}[/latex]

9. [latex]y=6{x}^{4}[/latex]

11. [latex]y=\frac{18}{{x}^{2}}[/latex]

13. [latex]y=\frac{81}{{x}^{4}}[/latex]

15. [latex]y=\frac{20}{\sqrt[3]{x}}[/latex]

17. [latex]y=10xzw[/latex]

19. [latex]y=10x\sqrt{z}[/latex]

21. [latex]y=4\frac{xz}{w}[/latex]

23. [latex]y=40\frac{xz}{\sqrt{w}{t}^{2}}[/latex]

25. [latex]y=256[/latex]

27. [latex]y=6[/latex]

29. [latex]y=6[/latex]

31. [latex]y=27[/latex]

33. [latex]y=3[/latex]

35. [latex]y=18[/latex]

37. [latex]y=90[/latex]

39. [latex]y=\frac{81}{2}[/latex]

41. [latex]y=\frac{3}{4}{x}^{2}[/latex]
Graph of y=3/4(x^2).

43. [latex]y=\frac{1}{3}\sqrt{x}[/latex]
Graph of y=1/3sqrt(x).

45. [latex]y=\frac{4}{{x}^{2}}[/latex]
Graph of y=4/(x^2).

47. 1.89 years

49. 0.61 years

51. 3 seconds

53. 48 inches

55. 49.75 pounds

57. 33.33 amperes

59. 2.88 inches